This research project is composed of a series of interlocking studies aimed at better defining host parasite relationships in certain infections. These include investigations of the role of cell membranes and lysosomes in the phagocytic function of human polymorphonuclear leukocytes; studies of the cellular and humoral factors influencing clearance of Candida albicans from the blood stream; studies of the physicochemical properties of gonococcal and other L-phase variants that may influence their role in human disease; investigations of antigenic heterogeneity among gonococci, and studies of factors influencing the risk of parenteral fluids and nutrients.